Method of forming carboxylic substituted amines



Patented Oct. 3 0, 1945 :UNITED-l Pri-TEN r;

"METIDDFKRMINGCAREQXmCii SUBSTITUTED Frederick@ erswortfhverona, N. J as'si'gnor- 'to' VThe` Mar'tin.Dennis-Company, Newark, N. J.; a corpratin'of'N'w' 'Jersey -No Drawing. ApplcatiohfMay 131943,11?,

Serial No. 485,342.1:

llhis.inventio'n:relatesit@ichemistryfan@ more2 particularly-Lto organic chemistry andgha-s` for--its`.- objeet -lthe-provis'ionfof. 3a imethodi oif producing. .A carboxylic acid substituted aliphatican-riries Anotherobj'ectistor-providefa method ofs-fcon- 5 lStill'i'another: obj ect Hisilto'iprovideswmf-athcmlr-of--" converting :glycine intoi-a f' carboxylic iacid substiw tute(11am-ine.l

Other objects zwilbbevapparent lasithe iilweriA tionhereiria'fter.ismoremHydiscMsed:

Infaccordance :with @these-objects' I havewdsw covered thatiwhenithe m'et'al salt fof lian" alpha aminosacidris'abrought :fintov reactive r'contact vWthwl anialiphaticf .rno'nodorJl 'poly lamine 4"fitllarr'ielevfated -lf: temperature sat-which fthelsaidsaltrand amihare'fi in a liquid phase, the alpha aminolori'minfo Lntro;l genfgroup-ofl themcidislconverted by ftliedamino is evolved fand 'the-1 carboxylic acid-rsiduel of-them alphalam-ino acidabecomes afsubstituent `,"gfrorip'fin'f the :amine Ufo'rminglslth'erewith a 'lmetalffsaltfiofa-l carboxylic acid substituted amines:-

This reaction mayibe--most'asimlpwlillustrated'iz by the fllowinglqu'ations :i

orariI alpha ammo-acid;attached-,wrheraiahafch :50

group ofthe alji'ohaarnirio aci'ds maybe displaced been stabilized' ametal 'salt'toiorm"carboxylic Aacid substituent' "groups" in the" amine opens up a widerd oforgariicL-synthsis" reactions' and 'proT vdesta way. of 'forming' la 1ar`ge number'iofsub` stitutedaminesthat'he'retofdre have not been" lutions" at"elevat'ditrriperatures; I have discovered tlfatfbyl heating' ari vaqueous-sohltion of acidprfiamy'fone-containing 'from 20v to .50% of the-saidfsa1t, to a temperature; approximating tri atmosphere :by aninert gas such las nitrogen;

Ondlly; am'll 1315131,""COItavi's",` '2lb-least T0116 amino mi;'rogerrgroupL 'attacneds'dirctly 'to' anialiplffatic carbon, which group contains at least Vorie (disfp1a"ceable"faminohydrogen; the 'amino hydrogen of. the aminef 'displ'abes 'the "alpha amino nitro"- ge'ngroup'of thealph'a acid WithevolutionY of 'am-f monia and with resultant'substitutioniof thecar-A boxylic residue of vthe acidonto the amino nitrogen of the amine. In the case-of a secondary amine, a mono substituted product is obtained;

Iriterpretmglthe-above equarionsrRR'fNHfis 551m the case of a 'primary'amme either a mono amine for such substitution, and th'e"'extent" to which the substitution-reaction is carried.

As one specific example of the present invention, but not as a limitation thereof, I will describe the same as it has been adapted in the formation of the substituted amines derived ffrom glycine. As hereinabove disclosed glycine (H.cH.coon) l Y NH2 is the lowest or simplest member vrtho homol- ,jj

ogous series of alpha amino vacids and isalsozl.

the most common of these acids. It is recognized chemically as being an amphoteric compound which in its pure or neutralstate exists as an ammonium salt byinteraction between; the acid carboxylvgroup and the basic amino nitrogen group. When the carboxylic acid groupis stabilized such as by reaction` with a metal ion displacing the acid hydrogen therein to form a metal salt, such as an alkali metal '(Na) salt, the amphoteric nature of the'acid"disappe'ars and the salt in aqueous solution reacts `as the compound The aliphatic amine in total amount providing'.` one' displaceable amino hydrogenffor each alpha A amino 4nitrogen `group1 presentfi'n"` the ,salt .is .l .ed to a refluxing temperature. Heating of 'thfejs'olu f added to the soiuuon', 'and the solution isrr tionjat' a refluxingjtemperature is continuedunu.

til 'no `further evolution of ammbnia (15H-Ii)` yisipbtained.V` The solution is thenl cooledtoatm'osplieric'temperatures and the substituted amine product is recovered from the solution inany convenient manner. In general', to recover the saltof the substituted amine', it is' only'necessary to remove the water, for example;V by vacuum drying. Some of the substituted amines may be precipitated as acid compounds and Washed'free of the water solution of the metal salt. WithV others an acid salt of the substituted amine 'may` be formed and the metal constituent of the amine precipitated from the solution. Other methods are available to obtain'the separation of the carboxylic substituted aminefrom the aqueous solution in which it is formed. Y

In the specific example given, when a monoamine such as propylamine (C3H'i-NH2) is employed, the substituted amine product obtained with glycine has the formula: l, A Y

1 H.CH.C com CiHLN v aoacoon j In the preparation of this fil-substitution product one molecular weight of the amine ls added to two molecular weights of the amino acid salt.

Dipropylamine (C3Hv)2NH, in the proportion of one molecular weight of the amine to one molecular weight of the aniino acid salt, yields themonosubstituted compound:`Y f j j *i "Ethylene diamine (Nm-CH-cHz-NHZ) in the proportion of one molecular weight diamine to vfrom one to four molecular weights of the amino acid salt, yields the mono to tetra carboxylic acid substituted product, the latter compound of 115,

which conforms to the formula- "iio'odonj H.oH.oooNa 'l Nontonm aoooonn H.CH.oooNa Other diamines wherein R2 equals (CH2M in which5n equals the numeral,2 or-more, such as tri `methylene diamine -to penta methylene` diamine, yield an analogous series of carboxylic substituted amines.l

By the substitution of: theA sodium'g-salt of Yalal nine orleucine, for the -sodium'salt offglycne in the above specilie examples, the corresponding carboxylic acid salt residues of theseacidsmemaining after vthe.- removal ofv the alpha-A amino groups of these acids, are the substituent carboxylic acid groups in the compoundsnoted above. All of the salts of ,thesubstituted aminov acids obtainabler by the practice of the present invention, as wellas the acids-*and esters of said acids,

havel beenjfound to have AWide utility jas ,extenders Yandplasticizers for naturaland artiliixrlrub ber, .impartingV desirable propertiesgto vthe vulcany ized v rubber compounds. i

The :esters pf the, said A acids, particularly those ingwhich'-the1nitrogen;is tertiary are. theonly known nitrogen-,containing compounds compati-r Y blewith the vinyl-,type resins, such as Koroseal,r vinyl-,butyralresins etc., /acting as nitrogenconnew propere.

taining plasticizers and o imparting tiesto the plasticized products.l l

They may also be used;as villliiermediatesfin Afurther organic synthesis; as cle-ionization agents, wetting agents, leveling agents in dyeing, emulsifying agents, flotation agents, surface acting agents, and from them base-exchange resins may be produced.

As the length of the aliphatic carbon chain of the amine employed increases and as thel length and complexity of the "X structure Yof the alpha amino acidincreases and also as the number of amino groups of the amine increases, carboxylic substituted amines of widely varying chemical and physical properties will be obtained. The lalkali metal salts of these substituted amines 'are generally soluble in water, as are also a large number of other4 metal salts.

In the practice of this invention using amines that are insoluble in water or which at the temperature ofheating are solids, I have found it advantageous to employ a Anon-reactivesolvent such yas a. tertiary alcohol to promote YIl'ts/ciblitlrA and reactive contact in; the solution. A l

An excess of the amine may alsdbe employed" l,

to assist in 'maintaininga liquid phase reaction In'tthepractice .offthis invention iatheqforri ing of the poly carboxylic substituted amines, I have also found it advantageous to employ an excess of the metal oxide' or hydroxide compound of the metal constituent of the amino acid salt, particularly where the metal constituent at the temperature of heating or at the dilution employed is highly ionizable, to suppress the formation of amine salts by reaction of the carboxyl group with the strongly basic amine and also to suppress amide formation by reaction of the carboxyl group with the ammonia (NH3) as evolved.

-For example, in the forming of the carboxylic substituted products of ethylene diamine, and of the tri, tetra, penta- (etc.) methylene diamines, I have found it advisable to employ a suiclent amount of caustic alkali to provide a pH approximating 9.5 in the aqueous solution of the sodium salt of glycine, in order to prevent and inhibit the formation of amine salts and amides.

It is believed apparent from the above disclosure of the present invention that the same may be widely varied without essential departure therefrom and all such modiilcations and adaptations are contemplated as may fall within the scope of the following claims.

What I claim is:

1. The method of producing carboxylic substituted amines which comprises heating an aqueous solution, containing a water soluble salt of an alpha amino acid and an aliphatic amine having at least one amino nitrogen group attached directly to an aliphatic carbon with said nitrogen group containing at least one displaceable amino hydrogen to a temperature approximating the boiling point of said solution under a reiluxing condenser and under a positive pressure of uncondensible gases.

2. The method of claim 1, wherein the relative proportions of said salt and said aliphatic amine approximates that providing one displaceable amino hydrogen in the amine for each alpha amino group of the alpha amino acid.

3. Th'e method of claim 1, wherein the said salt consists of an alkali metal salt.

4. The method of claim 1. wherein said alpha amino acid consists of one of the acids of the group consisting of glycine,v alanine and leucine.

5. The method of claim l, wherein said aliphatic amine consists of propylamine.

6. The method of claim 1, wherein said allphatic amine consists of ethylene diamine.

7. The method of claim 1, wherein said aliphatic amine consists of a polyamine and wherein said salt consists of the alkali metal salt of said alpha amino acid and wherein the said solution contains an alkali metal hydroxide in an amount suilicient to provide a pH of about 9.5 in the solution.

8. The method of claim 1, wherein the said solution contains a proportion of a solvent for said amine.

9. The method of producing carboxylic substi-l tuted amines which comprises forming an aqueous solution containing an alkali metal salt of glycine and propylamine each in such relative amounts providing a displaceable amino hydrogen in the amine for each alpha amino nitrogen group in the said glycine salt and heating th'e said Asolution under a reiluxing condenser and under a positive pressure of uncondensible gases to a temperature approximating the boiling point of the solution until ammonia evolution from the solution ceases, cooling the solution to atmospheric temperatures and separating the carboxylic substituted amine product from the solution.

l0. The method of forming a carboxylic substituted polyamine which comprises forming an aqueous solution containing an alkali metal salt of glycine, ethylene diamine and an alkali metal hydroxide in the relative amounts providing four molecules of the salt for one molecule of the diamine and for a solution pH of about 9.5, and heating the solution under a reuxing condenser and under a positive pressure of an uncondensible inert gas to a temperature approximating the boiling point of said solution until ammonia evolution from the solution ceases, cooling the solution, and separating the carboxylic substituted amine product from the solution.

FREDERICK C. BERSWORTH. 

